title: [Cystatin C--modulator of immune processes].
abstract: Cystatin C is a lowmolecular protein (13 kDa) that inhibits the activity of lysosomal cysteine proteinases with the strongest activity against cathepsin B and H. The recent experiments show that the level of cystatin C is independented of chronic and acute inflammatory process which frequently coexist with end stage renal diseases. Recent studies challange the theory because a higher concentration of cystatin C in serum correlated well with a higher concentration of inflammatory markers such as a CRP and fibrinogen in the patients. In vitro experiments on cultured monocytes and macrophages discovered that after stimulation by LPS and INF the expression of the cystatin C gene and synthesis of this protein was reduced. Cystatin C plays important modulatory function in regulation of the natural immunity, protecting our body against viruses, bacteries and parasites. Moreover, cystatin C binds the C4 component and modulates activation of the classical complement pathway. The experiments also show that cystatin C could influence non-specific immune response through the inhibition of the superoxide anion generation (respiratory burst), phagocytosis, chemotaxis and apoptosis of neutrophils. Similarly, the cystatin C can modulate the specific immune response through the inhibition of cathepsin S, bindining membrane receptors for TGF-beta or increasing MHC class II expression on dendritic cells.
authors.affiliation: Zakład Patofizjologii i Immunopatologii Wysiłku. nwittek@gazeta.pl
authors.forename: Natalia
authors.initials: N
authors.lastname: Wittek
authors.forename: Ewa
authors.initials: E
authors.lastname: Majewska
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002097:C-Reactive Protein / Q000378:metabolism; D002403:Cathepsins / Q000037:antagonists & inhibitors; D002478:Cells, Cultured; D055316:Cystatin C / Q000097:blood* / Q000235:genetics*; D005340:Fibrinogen / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D007113:Immunity, Innate / Q000502:physiology*; D007249:Inflammation / Q000276:immunology; D008264:Macrophages / Q000378:metabolism; D009000:Monocytes / Q000378:metabolism
chemical_list: D015415:Biomarkers; D055316:Cystatin C; D005340:Fibrinogen; D002097:C-Reactive Protein; D002403:Cathepsins; C028217:cathepsin S